As electronic apparatuses that constitute cellular phones, portable terminals, and portable image capturing devices, those are known that include a sliding device for an electronic apparatus that allows a sub body part to slide in a plane direction relative to a main body part.
For example, in cellular phones, a numeric keypad or a microphone is provided in the main body part, and a liquid crystal display unit and a loudspeaker are provided in the sub body part. A closed state in which the numeric keypad is housed may be selected when not in use, and an open state in which the numeric keypad is exposed in front of the liquid crystal display unit may be selected when in use. With this, a calling state in which the loudspeaker is positioned at an ear of a user and the microphone is positioned near the mouth or jaw of the user may be selected in cellular phones.
In this sliding device for an electronic apparatus, compared with that using a hinge mechanism, an opening or closing operation that causes the sub body part to slide relative to the main body part may be completed by pressing the sub body part in an opening direction or a closing direction alone at the initial stage of the operation, so that it is possible to make it easier to perform the operation with a single hand.
In addition, there is the advantage of not necessitating the supporting of the moment that is caused to act on the main body part by the radial bulge of a radially outside end portion of the sub body part relative to the hinge center caused by the rotation of the sub body part and the reaction of the rotation of the sub body part during an opening or closing operation. This allows a user to perform a sliding operation for an opening or closing operation with more ease and without taking the interference of the sub body part with the surroundings or inadvertent dropping into consideration.
Patent Document 1 discloses an electronic apparatus that includes a sliding device for an electronic apparatus as described above. The sliding device for an electronic apparatus illustrated in Patent Document 1 adopts a configuration where a sliding plate fixed to a sub body part is slidably connected to the base plate of a main body part through guides and rails.
Further, the sliding plate is connected to the base plate through a spring whose urging force reverses its direction during a stroke. As a result, a reaction force against a user's operation is provided in the first half of an opening operation, and an assisting force to the user's operation is provided in the second half of the opening operation. These reactive and assisting forces cause an operating force accompanying a user's sliding operation to be substantially required only in the first half of the opening operation, thus improving operability for a user.
In the sliding device for an electronic apparatus having such a configuration, the overall shape is particularly a parallelepiped shape having a laterally elongated rectangular bottom surface, and the amount of overlap of the sub body part and the main body part in an extended state is required to be as small as possible in the case of causing the sub body part to vertically slide relative to the main body part under the condition of vertical sliding directions.
As described above, in electronic apparatuses in particular, an input device such as a numeric keypad or a keyboard is often provided in the main body part, so that there tends to be a strong demand for as large an exposed surface as possible of the main body part in an open state, that is, an extended state, in view of ensuring user's convenience.
That is, in a state where the sub body part is slid and extended relative to the main body part, it is requested that the amount of overlap of the sub body part and the main body part in a sliding direction be reduced as much as possible and the exposed surface of the main body part resulting from the sliding of the sub body part in an opening direction be increased as much as possible, that is, the area of the main body part hidden by the sub body part be reduced as much as possible.
In the extended state, however, it is also necessary to ensure the stability of the sub body part at the time of a user's operation and the robustness of parts contributing to sliding including a sliding part and a slid part. Therefore, it is simultaneously requested that the sliding part and the slid part be held, that is, overlap, for a certain length. This also makes it necessary to ensure a certain amount of overlap of the sub body part and the main body part.